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How can you tell using a reaction profile if the reaction is exothermic or endothermic?

For an EXothermic reaction energy EXits the reaction meaning that there is more energy at the start than there is at the end. In a reaction profile this is shown by a drop of energy from the reactants to the...
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Answered by Jemilla C. • Chemistry tutor
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Explain why ionic compounds (e.g. NaCl) are soluble, and why they conduct electricity in this state.

Ionic compounds have a 'giant' ionic lattice structure. 'Giant' just essentially means that a basic unit is being repeated. In the case of NaCl, the ionic lattice would consist of the ions Na+ and Cl-. Water...
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Carbon dioxide is a gas at room temperature while silicon dioxide is a solid at room temperature with a melting point of 1770°C. Explain this by comparing their particles and those forces between these particles.

Although C and Si are both group 4 elements, C is much smaller than Si and can form double bonds with two oxygen atoms whereas Si is larger and so forms single bonds with four oxygen atoms. This means that c...
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How many moles are in 50g of NaCl.

Using the formula mass=Mr * moles we can rearrange this so it equals moles= mass / Mr. We are told the mass of the NaCl is 50g however we need to work out the Mr (relative formula mass) of the NaCl too. We d...
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Answered by Katy H. • Chemistry tutor
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Why is the boiling point of water significantly greater than that of other group 6 (16) hydrides?

Water exhibits hydrogen bonding between neighbouring molecules, where other group 6 hydrides are held together by much weaker (ca. 10 x) Van Der Waal's forces of attraction. Waters hydrogen bondong ability a...
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Answered by Joe S. • Chemistry tutor
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